Battle against taggers makes its mark as San...

1of5David Yu from the Department of Public Works takes a paintbrush to a tagger’s vandalism in Hang Ah Alley.Photo: Michael Short / Special to The Chronicle

2of5Department of Public Works graffiti unit employee David Yu paints over graffiti on an electrical box on Columbus Avenue in San Francisco.Photo: Michael Short / Special to The Chronicle

3of5People pass by as Department of Public Works graffiti unit employee David Yu paints over graffiti in Hang Ah Alley in San Francisco, Calif., on Thursday, December 27, 2018.Photo: Michael Short

4of5Graffiti covers a metal grate on a San Francisco sidewalk.Photo: Michael Short / Special to The Chronicle

5of5Department of Public Works graffiti unit employee David Yu cleans graffiti from a metal grate on Columbus Avenue in San Francisco.Photo: Michael Short / Special to The Chronicle

They usually strike at night. Spray can in hand, they scrawl their crude tags on San Francisco’s historic brick facades, business windows and sidewalks.

And when morning reveals the destructive spree of graffiti, the vandals are usually long gone, leaving property owners with a stubborn cleanup job — possibly even a fine.

But thanks to an aggressive new strategy by police and prosecutors, such incidents of vandalism appear to be in decline, according to the latest numbers. Reports of graffiti to 311 have hit an all-time low since the city started tracking the data at the start of 2016.

There were 3,371 such calls in November compared with 7,611 reported during March, according to data provided by the district attorney’s office.

“I know what it feels like to have my property vandalized — it’s disheartening,” said Sgt. Marty Ferreira, who heads the San Francisco Police Department’s graffiti unit. “I don’t think there’s any excuse for destroying another person’s property, and the fact that it’s so expensive to remove is inexcusable.”

A debate about whether graffiti is art or merely a public nuisance has heightened as street art has gone mainstream. But those disputes often don’t involve the crudely sprayed nicknames and scribbles that damage businesses, historic buildings and private homes — and do little beside boost a tagger’s online profile and ego.

San Francisco District Attorney George Gascón said such graffiti costs the city “millions and millions every year” to clean up. But most of the damage, he said, is only done by a small number of vandals who stay anonymous and share their work on social media.

Catching and stopping perpetrators, though, has been tough in the past. Often, when police caught one of the perpetrators, it was hard to make the low-level charges stick.

“We were taking some of these cases to court, and we were getting decimated by the judges or juries,” Gascón said. “The judges don’t like them, and the juries don’t like them.”

Department of Public Works graffiti unit employee David Yu’s iPad displays sites where graffiti has been reported for Yu and co-worker Allen Li to clean.

Photo: Michael Short / Special to The Chronicle

So rather than fruitlessly chasing after individual offenses, the district attorney’s office, Police Department and business community started focusing on building substantial cases against the worst perpetrators.

By documenting the vandals’ numerous tags, collecting security video of them in the act, and uncovering online postings of the handiwork, authorities have been able to follow their path of destruction.

“We identified and started cataloging these things and started finding who’s doing it, identifying them through their graffiti,” Gascón said. “One of the things with graffiti — taggers are proud of their work.”

In the most recent takedown in July, the district attorney’s office obtained a grand jury indictment with 52 felony counts of vandalism against seven serial sprayers.

Among the group was Tyler Kent Ross, who tagged up bus stops, businesses and anything else within reach of a spray can with rough renderings of Bart Simpson, prosecutors said. The work was well known in underground graffiti circles, but few knew the man alleged to be behind the notorious tags until Ferreira and the district attorney got involved.

Ross, a 27-year-old described by police as a transient, was arrested in March shortly after spraying his tag on the Wong Lee Bakery in Chinatown, officials said. Investigators said they determined he was good for 29 felony counts of vandalism in San Francisco at the grand jury proceeding.

Department of Public Works graffiti unit employee Allen Li scrubs graffiti from a plaque in Hang Ah Alley in San Francisco.

Photo: Michael Short / Special to The Chronicle

Ross’ attorney did not reply to requests for comment.

“There is a lot to know about how graffiti culture works and how nuanced these cases are,” Ferreira said. “The majority of people who are getting arrested are adults. They’re not kids.”

And the home and business owners that get vandalized may face headaches beyond the time and cost associated with cleaning up the mess. When the San Francisco Department of Public Works sees graffiti, workers post a notice that gives the owner 30 days to clean it up.

If it’s still around after that time, the property owners are issued a notice of blight that comes with a $320 fine. If the graffiti or tagging is not removed another 15 days after that, the city cleans it up and bills the property owner for the work.

Many businesses in the neighborhoods most targeted by taggers — like Chinatown, Fisherman’s Wharf and South of Market — say they depend on a tough graffiti policy.

Graffiti and tagging can contribute to an overall feeling of lawlessness in a neighborhood, which can encourage more crime and disorder and lead to even more serious trouble, according to the “broken windows theory” propounded by some criminologists.

“Anywhere you have graffiti, especially a lot of graffiti, people don’t feel safe,” said Randall Scott, executive director of the Fisherman’s Wharf Community Benefit District. “In the city, you want to feel clean and safe, and having less graffiti is a step in the right direction.”

Building on the recent success in the fight against graffiti, Scott has pushed to get more cameras at Fisherman’s Wharf, which has helped investigators like Ferreira build stronger cases.

“The end result is a lot of these taggers are getting prosecuted,” Scott said. “If you look at the stats, pretty much across the board graffiti is down.”

Evan Sernoffsky is a reporter for the San Francisco Chronicle specializing in criminal justice, crime and breaking news. He’s covered some of the biggest Bay Area news stories in recent memory, including wildfires, mass shootings and criminal justice reform efforts in San Francisco. He has given a voice to victims in some of the region’s biggest tragedies, carefully putting himself in challenging situations to make sure their stories are told. He works out of San Francisco’s Hall of Justice where he keeps watch on the city’s courts and hits the streets to expose the darker side of a city undergoing rapid change. He moved to the Bay Area from Oregon where he grew up and worked as a journalist for several years.